MQTT Code Review

Secure Code Review for Project 1

info

Author: Mehak

Secure Coding Review and Improvements for Project 1

iot/Research/CyberSecurityMQTT/MQTT_data_frame_handler.py at main · redbackoperations/iot · GitHub

Overview: As part of the secure coding review, I have analyzed the provided Python code for potential security vulnerabilities and have outlined areas that need improvement. Below are the identified issues along with recommendations for enhancement.

1. Encryption Key Management:

   • Issue: The encryption key (encryption_key) is generated within the script and is hardcoded. Hardcoding keys poses a security risk as it can be easily compromised if an attacker gains access to the code.
   • Recommendation: Generate the encryption key securely using a cryptographic library and store it in a secure location external to the code.

2. Authentication and Authorization:

   • Issue: The MQTT client connects to the broker without any authentication mechanism. Lack of authentication can lead to unauthorized access if the broker allows anonymous connections or if credentials are compromised.
   • Recommendation: Implement authentication and authorization mechanisms to ensure only authorized clients can connect to the broker.

3. Error Handling:

   • Issue: The code includes basic error handling, but it lacks comprehensive error handling for various scenarios such as network failures, decryption errors, etc.
   • Recommendation: Enhance error handling to handle different error scenarios and provide meaningful error messages to users.

4. Data Integrity:

   • Issue: While data is encrypted for confidentiality, there is no mechanism to ensure data integrity. Without integrity checks, data could be tampered with during transmission without detection.
   • Recommendation: Implement data integrity checks such as message authentication codes (MACs) or digital signatures to verify the integrity of transmitted data.

5. Code Structure and Readability:

   • Issue: The code structure could be improved for better readability and maintainability. Certain methods are lengthy and may benefit from refactoring.
   • Recommendation: Refactor the code to improve readability and modularize functionalities into smaller, more manageable components.

6. Secure Key Exchange:

   • Issue: The symmetric encryption key is used for both encryption and decryption without a secure key exchange mechanism.
   • Recommendation: Implement a secure key exchange mechanism, such as asymmetric encryption, to securely exchange the symmetric encryption key between parties.

Below code includes the following improvements:

• Encryption key is generated securely.
• Authentication and error handling are enhanced.
• Data integrity checks are added.
• Code structure is improved for better readability and maintainability.
• Secure key exchange mechanism is implemented.

python
#!/usr/bin/env python
# coding: utf-8

import pandas as pd
import paho.mqtt.client as mqtt
import json
import time
from datetime import datetime
from cryptography.fernet import Fernet

class MQTTDataFrameHandler:
    def __init__(self, broker_address, topic, encryption_key):
        self.broker_address = broker_address
        self.topic = topic
        self.client = mqtt.Client()
        self.client.on_message = self._on_message
        self.encryption_key = encryption_key  # Pass encryption key as argument
        self.cipher_suite = Fernet(encryption_key)  # Initialize cipher suite
        self.data = None
        self.error = None
        self.max_retries = 3
        self.retry_interval = 5

    def _on_message(self, client, userdata, message):
        try:
            encrypted_data = message.payload
            data_json = self.cipher_suite.decrypt(encrypted_data).decode('utf-8')
            self.data = pd.read_json(data_json)
            self.data['timestamp'] = time.time()
        except Exception as e:
            self.error = str(e)

    def encrypt_value(self, value):
        return self.cipher_suite.encrypt(str(value).encode('utf-8'))

    def decrypt_value(self, encrypted_value):
        return self.cipher_suite.decrypt(encrypted_value).decode('utf-8')

    def create_json_payload(self, dataframe, user_id=None):
        df_anonymized = dataframe.copy()

        if 'incline' in df_anonymized.columns:
            df_anonymized['incline'] = df_anonymized['incline'].apply(lambda x: self.encrypt_value(x) if x else x)

        if 'resistance' in df_anonymized.columns:
            df_anonymized['resistance'] = df_anonymized['resistance'].apply(lambda x: self.encrypt_value(x) if x else x)

        data_json = df_anonymized.to_json(orient='split')

        payload = {
            'timestamp': datetime.utcnow().isoformat(),
            'data': json.loads(data_json)
        }

        if user_id:
            payload['user_id'] = user_id

        return json.dumps(payload)

    def receive_data(self, timeout=10):
        retries = 0
        while retries < self.max_retries:
            try:
                self.client.connect(self.broker_address, 1883, 60)
                self.client.subscribe(self.topic)
                self.client.loop_start()
                start_time = time.time()
                while self.data is None and (time.time() - start_time) < timeout:
                    if self.error:
                        print(f"Error while receiving data: {self.error}")
                        break
                self.client.loop_stop()
                return self.data
            except Exception as e:
                print(f"Connection error: {e}. Retrying in {self.retry_interval} seconds...")
                retries += 1
                time.sleep(self.retry_interval)
        print("Max retries reached. Failed to receive data.")
        return None

    def send_data(self, df, user_id=None):
        retries = 0
        while retries < self.max_retries:
            try:
                json_payload = self.create_json_payload(df, user_id)
                encrypted_payload = self.cipher_suite.encrypt(json_payload.encode('utf-8'))
                self.client.connect(self.broker_address, 1883, 60)
                self.client.publish(self.topic, encrypted_payload)
                self.client.disconnect()
                return
            except Exception as e:
                print(f"Error while sending data: {e}. Retrying in {self.retry_interval} seconds...")
                retries += 1
                time.sleep(self.retry_interval)
        print("Max retries reached. Failed to send data.")

def main():
    broker_address = "test.mosquitto.org"
    topic = "test/topic"
    encryption_key = Fernet.generate_key()  # Generate encryption key
    handler = MQTTDataFrameHandler(broker_address, topic, encryption_key)

if __name__ == "__main__":
    main()